Preheat oven to 350. Cut chicken into cubes. Season with salt & pepper. Heat oil in large skillet & cook chicken until browned, about 5 to 8 minutes. Stir in beans, 1/2 cup pasta sauce, & 1/2 cup of cheese. Remove from heat. Combine remaining pasta sauce & salsa in separate bowl & spread 1 cup across a 13 x 9 baking dish. Place two tortillas over sauce & then spread half of chicken mix on top. Make another layer of tortillas and then top with remaining chicken, cheese & sauce. Cover with foil and bake for 25 mins. Serve with a bit of sour cream, if desired.